This invention relates to drains having unclogging devices to facilitate the flow of liquids through the drains.
Drains are used for many purposes to remove liquids from holding tanks, conduits and the like. In some cases the drains are used to remove liquids which are capable of clogging the drains. One example is drains for black liquor holding tanks used in pulp mills. Conventionally such drains are often equipped with a ball valve and consist of a short vertical section of pipe extending downwardly from the black liquor holding tank. These often become clogged due to solid materials commonly deposited by black liquor. In the past these drains have been customarily unclogged by poking rods upwardly through the drains after the ball valves have been opened. This can pose a significant risk to workers because black liquor can cause chemical or thermal burns, particularly hazardous to workers' eyes. Sometimes the drain suddenly becomes unclogged, causing a surge of dangerous liquid to come out of the drain and spray nearby workers.
In addition there is a significant environmental risk using such conventional drains. The drains may appear clogged and therefore are left unattended after the ball valve is opened and before the obstruction is cleared. In the past this has caused serious accidents where black liquor suddenly makes its way through the drain and floods the surrounding area.
Accordingly it is an object of the invention to provide an improved drain apparatus with provision for unplugging the drain without posing a hazard to people operating the device or located nearby.
It is another object of the invention to provide an improved device of the type which accomplishes the task of unplugging drains better than prior art devices and methods.
It is a further object of the invention to provide an improved device of the type which is simple, rugged in construction and durable.
It is a still further object of the invention to provide an improved device of the type which can be installed on existing drain outlets or the like.